Device for overcoming dead-centers



1N0 Medal.)

0; B. THOMPSON.

DEVICE FOR OVERCOMING DEAD CENTERS.

No. 318,881. Patented May 26, 1885.

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' motion of the wheel or shaft.

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OBRIN BARNES THOMPSON, OF JERSEY, OHIO.

DEVICE FOR OVERCOM ING DEAD-CENTERS.

SPECIFICATION forming part of Letters Patent No. 318,831, dated May 26, 1885.

Application filed J anuary 9, 1885. (No model.)

To (LZZ whom it may concern:

Be it known that I, ORRIN BARNES TrroMa SON, a citizen of the United States, residing at Jersey, in the county of Licking and State of Ohio, have invented certain new and useful Improvements in Devices for Overcoming Dead-Centers, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

In the accompanying drawings, Figure 1 consists of a front view of my improved de-' vice applied to a fly-wheel. Fig. 2 is a see tional view of the same. Fig. 3 is a front view, showing a modified form of my device. Fig. 4 is a sectional view of the modified form.

The same letters of reference are used to indicate identical parts in all the figures.

My invention relates to an improvement in devices for converting rotary into reciprocating motion where a shaft is rotated by a crank and pitman; and it consists in an arm pivoted at one end to a fly-wheel or crank and held in normal position by a spring. To the other end of the arm is pivoted a pitman so arranged that when the crank and pitman are in a line to produce a dead-center the force applied to the pitman moves the crank beyond the deadcenter, after which the spring forces the arm again to its normal position.

In the drawings I have illustrated my improvement as applied to a fly-wheel; but it is obvious that it is equally applicable to any form of crank.

A is an ordinary fly-wheel having its axis at B.

D is an arm pivoted to the wheel A at 0. Its other end is pivoted to the pitman E at e.

F is a spring bearing against the arm D in the direction opposite to the direction of the In Fig. 1 a straight spring is shown attached to the arm, and its free end resting against a pin, f, on the wheel.

K K are pins or stops limiting the throw of the spring or arm D, and are cushioned with a band of rubber. Any-convenient form of spring may be used, the only purpose of it being to press or draw the arm D in a direction opposite to the direction of the motion of the shaft.

In Figs. 3 and 4 is shown a modified form of the arm, in which it is represented attached to the wheel or crank and curved partly around the shaft or axis and held by the spring F. here a fly-wheel is used the arm I) may be attached directly to the hub of the wheel, if more convenient. When the pitman, the axis of the shaft, and crank are in a linethat is, in a position to produce a dead-centerthe arm D stands at an acute angle to such line. In operation, therefore, whenever the crank, pitman, and axis are in a line to produce a dead-center the force applied to the pitman moves the arm D, as shown by the dotted lines, instantly breaking the line which produced a lock or dead-center, so that the force applied to the pitman operates upon the crank to revolve the shaft. The dead-center point being passed, the spring restores the arm to its normal position ready for the next halfrevolntion of the wheel or crank.

I do not limit myself to any form of arm or spring, the only essential being that the arm shall always stand at an acute angle to the line of dead-center in which the pitman, crank, and axis of the shaft are points.

Having thus fully described my invention, I claim-- 1. In a device for overcoming dead-centers in any crank-movement, an arm pivoted at one end to the crank and at the other to the pitman, and pressed by a spring in a direction opposite to the direction of the motion of the shaft, and so arranged as always to stand at an acute angle to the line of dead-center, substantially as described.

2. In a device for overcoming dead-centers, the arm D, pivoted at one end to the wheel or crank and at the other end to the pitman, in combination with a spring and stops K K, substantially as and for the purpose described.

3. In a device for overcoming the dead-centers in a crank-movement, the pitman E, pivoted to a spring-actuated crank-arm, so that power applied to the pitman moves the crank beyond the dead-center line, substantially as and for the purpose described.

4. In adeviee for overcoming dead-centers, to the fly-Wheel or arm from the shaft and :0 a flexible crank consisting of two or more held in place by a spring and stops, substanpieces or arms attached together by pivots tially as and for the purpose specified. and 2t spring, so that the crank may always be moved by the pitman out of the dead-cen ORRIN BARNES THOMPSON.

ter line, substantially as described.

5. In a device for preventing dead-centers, \Vitnesses: a spring-crank composed of the fly-wheel or E. \V. REOTOR,

an arm from the shaft, and the arm D, pivoted OTTO RICHTER. v 

